The present invention relates to the domain of the estimation of hydrocarbon (i.e. oil) resources in the subsoil and especially the domain of the determination of oil saturation in the sub soil.
The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. Furthermore, all embodiments are not necessarily intended to solve all or even any of the problems brought forward in this section.
Determining the volume of the fluids (water, oil, etc.) in the subsoil may be a key factor to adequately estimate the economic value of a given field: in particular, hydrocarbon production depends on porosity, saturation, wettability, pore pressure, matrix permeability and hydraulic fractures.
It may be important to distinguish the different fluids in the subsoil as each fluid has a different economic value and can have a different impact on the dynamics of the production.
Mineralogical variations, low permeability and the multiscale microstructure of the organic kerogen may also complicate the evaluation of these rocks.
Most of the known technics used to estimate the volume of fluids in the subsoil are based on simulations (and can be inaccurate) or are based on destructive analysis of rock samples (and thus, the rock samples cannot be used for other purposes).
If NMR technics may be known, it may be difficult to distinguish the oil and water in the NMR responses.
There is thus a need for non-invasively determining the surface dynamics of petroleum fluids (oil/water/gas) trapped in the complex microstructure of an oil-shale rock by analyzing the oil/water saturation of the subsoil.